全文获取类型
收费全文 | 235篇 |
免费 | 0篇 |
专业分类
化学 | 120篇 |
晶体学 | 68篇 |
力学 | 2篇 |
数学 | 15篇 |
物理学 | 30篇 |
出版年
2022年 | 7篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 9篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 1篇 |
2014年 | 5篇 |
2013年 | 17篇 |
2012年 | 7篇 |
2011年 | 6篇 |
2010年 | 15篇 |
2009年 | 9篇 |
2008年 | 15篇 |
2007年 | 8篇 |
2006年 | 13篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 13篇 |
2002年 | 13篇 |
2001年 | 4篇 |
2000年 | 8篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 4篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 3篇 |
1972年 | 3篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有235条查询结果,搜索用时 203 毫秒
21.
A new orthophosphate BaFe[PO4](OH) is obtained by hydrothermal synthesis. The unit cell parameters are as follows: a = 9.711(6), b = 8.991(5), and c = 4.912(2) Å; space group P212121. The structure has no features in common with the structures of three Ba-Fe phosphates studied. At the same time, the mixed framework, which is composed of five-vertex polyhedra of Fe and P-tetrahedra, exhibits a similarity to the frameworks of a number of alumosilicates belonging to the group of nepheline (nepheline NaAlSiO4, kalsilite KAlSiO4, and RbAlSiO4), as well as the beryllonite NaBePO4 beryllophosphate and H3O · ZnPO4 zin-cophosphate. All the frameworks contain six-membered rings which consist of alternating tetrahedra of different kinds with compensating cations at the ring centers. The topology of the new framework is most closely related to that of nepheline. Structures of this type are of interest as potential ion exchangers and ion-conducting materials. 相似文献
22.
O. V. Dimitrova M. V. Feigel’man 《Journal of Experimental and Theoretical Physics》2006,102(4):652-660
The effect of Rashba spin-orbit coupling on the supercurrent in S-2DEG-S proximity junctions is investigated in the clean
limit. A generalization of Beenakker’s formula for Andreev levels to the case of spin-orbit scattering is presented. Spin-orbit
induced splitting of Andreev bound states is predicted for an infinite-width junction with nonvanishing normal backscattering
at S-N interfaces. However, a semiclassical average of the Josephson current is insensitive to the Rashba coupling as long
as the electron-electron interaction in 2DEG is neglected.
The text was submitted by the authors in English. 相似文献
23.
24.
The contact between three insulators results in a set up of contact potentials related to the adsorbed dipole moment at each surface. The produced electric field applies force (disjoining pressure) on each interface. This disjoining pressure is a long-ranged force (1/distance2) which is proportional to the difference between the dielectric permittivities of the phases on the two sides of the interface and, for small angles, to the square of the contact angle. The contact potential leads to a logarithmic perturbation of the profile of the three-phase contact zone. 相似文献
25.
We characterize the maximal regular subsemigroups of the ideals of the semigroup of all order-preserving transformations as
well as of the semigroup of all order-preserving or order-reversing transformations on a finite ordered set. 相似文献
26.
Cheshmedzhieva D Ivanova P Stoyanov S Tasheva D Dimitrova M Ivanov I Ilieva S 《Physical chemistry chemical physics : PCCP》2011,13(41):18530-18538
Absorption and fluorescence spectra in acetonitrile for a series of substituted aryl hydrazones of N-hexyl-1,8-naphthalimide are studied with the aim of potential application of the compounds for enzyme activity localization. The influence of the substituents on the spectral characteristics has been evaluated. The absorption and fluorescence energies of substituted aryl-1,8-naphthalimide hydrazones have been calculated with the PCM TDDFT formalism. The M06 and PBE0 functionals, combined with the 6-31+G(d) atomic basis set, have been found to accurately model the excited state properties of the present set of solvated fluorophores. Absorption and fluorescence spectral characteristics have been rationalized in terms of experimental and theoretical electronic indices in order to assess their predictive abilities for application in designing analogues with good emitting properties. An excellent linear dependence is established between the experimental fluorescence and Hammett σ(p)(+) substituent constants and on the other hand σ(p)(+) constants correlate with the theoretically calculated values for the electrostatic potential at nuclei (EPN). A model for predicting the fluorescence properties of substituted hydrazones by means of EPN is drawn, including the polysubstituted derivatives, where Hammett constants are not applicable. 相似文献
27.
28.
29.
The activation of the catalytic persulphate oxidation of sulphanilic acid when the catalyst, silver(I), is suitably complexed, is discussed. 2,2'-Bipyridyl is proposed as activator as it accelerates the rate-determining step of the process-the oxidation of silver(I) to silver(II). The mechanism of activation is investigated and discussed in detail. On the basis of these investigations a catalytic method has been developed for the determination of silver(I), with a sensitivity of 4 x 10(-4)mug ml and +/-7.6% relative error. 相似文献
30.
Yordanov ND Dimitrova A 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2006,63(4):826-829
EPR study on the ligand-exchange reaction between bis(diethyldiselenocarbamato)copper(II), Cu(Et2dsc)2, and bis(octyldithiocarbonato)copper(II), Cu(octxant)2, in CH2Cl2, CHCl3, CCl4, C6H6 and C6H5.CH3 is reported for the first time. Mixing of equimolar amounts of the parents (chromophores CuSe4 and CuS4, respectively) in C6H6, C6H5.CH3 and CH2Cl2 makes EPR signals of both parents superimposed by the spectrum of a mixed-chelate Cu(xant)(dsc) complex (chromophore CuS2Se2). A new additional EPR spectrum appears in CHCl3 or CCl4 due to a five-coordinate mixed-ligand complex with the chromophore Cu(S3Se)S as follows by comparing the g-values of parents and mixed-ligand complexes. The appearance of this complex could be explained having in mind donor-acceptor properties of complexes, solvents and the resultant reaction of Cu(octxant)2 with the ester of diselenocarbamic acid yielded in Cu(Et2dsc)2 destruction by CCl4 or CHCl3. 相似文献